Bendy implant harnesses the power of your beating heart

Fancy becoming a real human dynamo? Every breath you take could one day be used to generate electricity.

Energy from the natural motion of the heart, lungs and diaphragm in cows, pigs and sheep has been harnessed to power medical implants. The hope is that people with pacemakers, cochlear implants and heart monitors will one day be spared risky surgery when the batteries need replacing. Instead, our organs would power our electronics.

John Rogers and his colleagues at the University of Illinois at Urbana-Champaign exploited the piezoelectric effect, in which crystal lattices in some compounds generate an electric current when flexed or compressed.

Video: Bendy implant harnesses the power of your beating heart

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The team manufactured nanoribbons of a piezoelectric material called lead zirconate titanate and deposited them on a flexible silicone base that could conform to the shape of a moving organ. These were connected to a rechargeable battery and implanted on the heart, lungs and diaphragms of the animals (PNAS, DOI&colon; 10.1073/pnas.1317233111).

“I think the concept of creating electrical power from motions in internal organs is really interesting,” says Rogers. “The key thing is, if you’re going to do this, you need to be able to achieve efficiency and ultimately power output that is of practical use.”

One challenge was finding a spot where the device can bend without dangerously constraining the body’s motion. The best place was at an angle on of the heart’s ventricles.

The group is not the first to explore devices that can harvest energy, but say they have made several important advances. Their system generated 0.2 microwatts per square centimetre of the piezoelectric material. This is enough, Rogers says, to power an off-the-shelf pacemaker. If more power is required, the nanoribbons can be stacked.

It was also the first time the system was tested in animals that are of comparable size to humans.

“This study is of high impact, great significance and outstanding applications,” says Zhong Lin Wang, a materials scientist at the Georgia Institute of Technology. Wang’s research team builds zinc oxide nanowires that can also grab energy from motion.

The next step is to test what happens when the device stays in the body for years at a stretch. That’s crucial before moving on to what the group really wants to do&colon; put the devices on human organs.

“If you look at the trends these days, you’re seeing more and more electronic implantable devices,” says Rogers. “I think there’s going to be a growing demand for in-body power.”